A quality extrusion depends a lot on the design of the nose of a pugmill. On this industrial pugmill at Plainsman Clays this is the custom design it took to prevent laminations and peeling at the edge of extrusions, especially on lower plasticity clay bodies. This nose assembly weighs about 70lb. It is fed by a long auger from a vacuum chamber. This design achieves compression by easing the extrusion outwards and then abruptly narrowing it.
The practice of removing air from clay as it is pugged. Deaired clay has better forming properties and produces a smoother fired surface.